Industrial derivatives of lignin lignosulfonates are produced during sulfite delignification of wood. They are characterized by a wide molecular weight distribution, polyfunctionality, and lack of crystallinity. The presence of hydrophobic and hydrophilic domains in the lignosulfonate macromolecular system determines the amphiphilic and polyelectrolyte properties of this biopolymer. As a polyelectrolyte, lignosulfonates (LSs) show complex conformational and phase behavior, which can be controlled by a wide range of external factors (ionic strength, medium acidity, solvent polarity, etc.). Herein, we present the results of a study of the associative behavior of three lignosulfonate samples with different molecular weight distributions (Mw 9250−46 300) and structural and cationic (Na + , Ca 2+ ) composition. The effects of the concentration of LS (0.2−200.0 g/dm 3 ), temperature (293−353 K), ionic strength of the medium (KCl, 0.08−0.80 mol), and ethanol additives (0.6−73.0 vol %) on the bulk and surface properties of lignosulfonates have been revealed. It was assumed that the LS association in solutions is a consequence of the processes of counterionic condensation with the formation of ionic pairs and multiplets. The binding of counterions is facilitated by an increase in the ionic strength of the medium and ethyl alcohol additives.
The expediency of processing iron-containing concentrate with low iron content, increased content of manganese and copper is considered in the article. To process such a concentrate, a metallization process is proposed to produce sponge iron with a reducing agent - carbon. It was found that in solid-phase reduction at 1150 °C iron is reduced to a greater extent, as well as small particles with a copper content of about 95%, manganese is not recovered. The simulation process of metallization with carbon at a temperature of 1250 °C shows that iron is mainly distributed in the metallic phase, to a lesser extent in slag phases, manganese is distributed in two phases - metal and slag, copper is presented as a separate phase of metallic copper in the composition with iron alloys, and also composes a part of iron alloys. The reduction degree from concentrate to the metallic part is 80 - 91% for iron and 95 - 98% for copper. The presence of metallized particles of various sizes, representing phases of iron with manganese and copper was found in the slags.
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